I have no problems with the characters being in World Showcase and it has been my experience that the Character meet and greets are primarily in the correct countries. Here is a list of characters that I have seen at World Showcase in the past few year.
Canada - Brother Bear Characters Koda and Kenai (sp)
United Kingdom - Winnie the Pooh, Tigger, Eeyore, Piglet, Mary Poppins, Burt, Cruella DeVil
France - Beauty and the Beast, Hunchback, Esmeralda, and the evil guy from Hunchback, I think his name was Clopin
Morocco - Aladdin, Jasmine, Genie, Jafar
Germany - Snow White, Dopey
China - Mulan, Mushu
Norway - All the Princesses, which is totally out of place. BRING BACK THE ORIGINAL AKERSHAUS
Mexico - The Three Caballeros
I don't think it would be fitting to see the characters outside theie respective countries in World Showcase. I am sure that Disney does have some characters that can be represented in every country at World Showcase and it would be cool to see more of the characters in those countries. Sometimes it seems to be a hit or miss thing because I don't think these character offerings are publicized much, except for maybe the Morocco, France and UK areas where it seems they have built specific meet and greet areas and many times even have a Photo Pass photographer there too. In the other countries they were just there in a corner of the pavilion like they just happened to be there at that moment.
I would not want to see it get out of hand and one day finding say, Belle and Beast in Japan, or even Mulan in Japan, or the Three Caballeros in front of The American Adventure, although with the way everything seems to be going with the spanish subtitles appearing everywhere, that is not so far fetched.
I have not seen any characters yet in Japan, Italy or the United States. United Statescould host a number of characters, but I can't recall any that would be appropriate for Italy or Japan as yet, except maybe The Power Rangers in Japan, but they are in Disney-MGM usually.
As for Norway, don't think Disney has any Norwegian charaters, but they did do that horrible injustice to Norway by putting the Princes character dining experience there. They ruined a fantastic Norwegian dining area (my favorite Epcot restaurant before the Princess' moved in) . The Princess' are from various countries and therefore are out of place in Norway.